Engineering change

Change or adaptation has always been a fundamental part of engineering design; the vast majority of product design activity consists of taking a current product, concept or solution and adapting it to meet a new set of requirements. This view, whilst seldom emphasised in text books on design, is supported by a number of authors, for example: ...most designing is actually a variation from or modification to an already-existing product or machine. (Cross, 1989) History matters - no design begins with an absolutely clean sheet of paper. (Bucciarelli, 1994) From a business perspective, changes to a design are "a fact of life" in taking a product from concept, through design and manufacture and out into the field (Nichols, 1990); they are the rule and not the exception in product development processes in all companies and in all countries (Clark and Fujimoto, 1991). From a high-level viewpoint, changes are made for two reasons: to remove errors from a product (rework) or to improve/enhance/ adapt it in some way. As an example of the importance of engineering change, a survey of German engineering businesses found that approximately 30% of all work effort was due to engineering changes (Fricke et al., 2000); this included rework as well as the adding of functionality to a product.Terwiesch and Loch (1999) reported that engineering changes consumed between a third and a half of the engineering capacity at the firm they examined, along with 20-50% of tool costs (Figure 10.1). The attitudes of engineers and managers towards engineering changes are important, as the ability of a company to implement changes effectively and efficiently is hugely dependent upon the people carrying out the task, and the way they communicate. Engineering changes are often perceived negatively because they can cause schedules to slip and budgets to overrun, but they can also be regarded as an opportunity for well-organised companies to meet the requirements of demanding customers rapidly and compete successfully with their rivals (DiPrima, 1982). The issue of engineering changes has been gaining prominence in industry over the past two decades due to dramatic changes in markets. Maull et al. (1992) state that the move from the seller-dominated markets of the 1970s and early 1980s to the buyers' markets of today has led to a situation of greater diversity in products, smaller production runs and shorter product life-cycles. An increasing volume of engineering change is the inevitable consequence of such an environment (Coughlan, 1992). Markets are now fragmented and populated by sophisticated customers who demand individualised offerings (Clark and Fujimoto, 1991). Today, there is also much more competition because of the increased globalisation of industries, such as automotive, aerospace and electronics. "The time when an innovatory product could be launched with confidence and remain unchallenged has passed" (Inness, 1994). In order to maintain or increase market share, companies must be constantly prepared to improve and update existing products, and rapidly introduce new ones. Engineering change has always been an important part of the product design and development process, but today it is an essential aspect. For businesses to survive and compete, gaining a thorough understanding of all the issues involved is a vital design research activity for industry in conjunction with academia. This situation may be summed up by the following statement: ... it's absolutely necessary to understand changes and to have a good grip on them as the entire product development process can be described as a continuous change management process. (Fricke et al., 2000) This chapter first takes a general look at engineering change and configuration management, as currently practised in industry.This is followed by definitions of change. The change life-cycle and a change process are then introduced. Finally, the impact of change and its relationship to a product's architecture are discussed.The purpose of this chapter is to define what is meant by an engineering change, to show when in the product life-cycle engineering change processes occur and discuss what their typical elements are.